1. Field of the Invention
The present invention relates to an ink filling apparatus and an ink filling method in which an ink tank including a storage chamber that stores ink via an ink absorber and a storage chamber that directly stores ink is filled with ink.
2. Description of the Related Art
Some ink tanks configured to supply ink to an ink jet print head have a first storage chamber including an ink absorber serving as a negative pressure generating member to store ink via the ink absorber, and a second storage chamber that directly stores ink. The first storage chamber includes an ink supply port and an atmospheric communicating port. The second storage chamber is a substantially closed space that is in communication only with the first storage chamber. The second storage chamber directly contains ink. As an ink filling method for such an ink tank, a method has been proposed which involves filling the ink tank with ink by reducing the pressure in the ink tank as described in U.S. Pat. No. 6,447,109 and Japanese Patent Laid-Open No. H08-207299(1996).
According to the method described in U.S. Pat. No. 6,447,109, a reduction in the pressure in the ink tank, filling of ink, and cancellation of the pressure reduction are performed through a communicating port formed on an upper surface of the ink tank. According to the method described in Japanese Patent Laid-Open H08-207299(1996), the pressure in the ink tank is reduced, using a vacuum pump, though the atmospheric communicating port positioned on the upper surface of the ink tank, while the ink tank is filled with ink through the ink supply port positioned on a lower surface of the ink tank.